1. Technical Field of the Invention
This invention relates to telecommunication systems and, more particularly, to a system and method of detecting and preventing fraudulent long distance telephone calls in a radio telecommunications network.
2. Description of Related Art
In existing radio telecommunications networks, fraudulent users may attempt to place free long distance telephone calls by causing the network to recognize the calls as being placed by a legitimate subscriber. Fraudulent users may clone the legitimate subscriber's mobile telephone, including the electronic serial number (ESN) and mobile identification number (MIN). Thereafter, the cloned telephone appears to the network to be the subscriber's legitimate telephone, thereby allowing a fraudulent user to place illegitimate long distance telephone calls.
Although there are no known prior art teachings of a solution to the aforementioned deficiency and shortcoming such as that disclosed herein, U.S. Pat. No. 4,955,049 to Ghisler discusses subject matter that bears some relation to matters discussed herein. Ghisler discloses a method of supervising subscribers in a mobile telephone system to detect fraudulent usage of a mobile telephone. Ghisler assigns a predetermined sequence of numbers to each mobile telephone in the system. Each time a call is made by a subscriber, the next number in the mobile telephone's assigned sequence is transmitted by the mobile station to the serving mobile switching center (MSC). The MSC records the numbers utilized, and detects a fraudulent call if there is a break in the sequence.
Ghisler, however, requires modification of each mobile station to store its assigned number sequence and transmit the next number in the sequence each time a call is made. It would be advantageous to have a method of detecting fraudulent telephone calls that does not require modification of the mobile station.
Review of each of the foregoing references reveals no disclosure or suggestion of a system or method such as that described and claimed herein.
In order to overcome the disadvantage of existing solutions, it would be advantageous to have a system and method of preventing fraudulent long distance calls by barring a mobile station's access to the network when certain conditions indicative of fraud are met. The mobile station would then be barred until the subscriber enters a proper personal identification number (PIN) code. The present invention provides such a system and method.